Limp incandescent mantle.



S. GULBRANDSEN.

LIMP INCANDESCENT MANTLE.

APPLICATION FILED mp2s. L916- 1 1 97,365 Patented Sept. 5, 1916.

I QM awa /M TED STATES Parana snip.

SVERRE GULBRANDSEN, OF WOODBURY, NEW JERSEY, ASSIG NOR TO WELSBACH LIGHTCOMPANY, OF GLOUCESTER CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

LIMP INCANDESCENT MANTLE.

Application filed January 29, 1916. Serial No. 75,04;

To all whom itmay concern:

Be it known that I, SVERRE GULBRANDSEN, a citizen of the United States,residing at WVoodbury, in the county of Gloucester and State of NewJersey, have invented a new and useful Improvement in Limp IncandescentMantles, of which the following is a full, clear, and exact description,reference being had to the accompanying drawings, forming part of thisspecification, in which Figure l is a side elevation partly in sectionshowing an .inverted limp mantle made in accordance with my invention inposition prior to ignition and use, and Fig. 2 1s a similar view showingthe mantle after shaping, under actual burning use.

Previous to my invention set forth in my Patent No. 1,133,470, datedMarch 30, 19 15, inverted gas mantles used for ordinary city pressures(2 to 8 water column) were of the ventilated type; that is, there was anannular opening at the top of the mantle between the burner nozzle andthe ring carrying the mantle, through which the products of combustionwere vented. Closed-top mantles, that is, mantles whose carriers orrings made a tight joint with the burner nozzle, were confined to use onhigh pressure systems.

In accordance with my patent above referred to, I discovered that asmall diameter closed-top limp mantle could be properly shaped andhardened under city pressures; and this discovery has led to awide-spread commercial use of the limp or rag mantles on burners usingordinary city pressure.

In addition to the discovery as to limiting diameters set forth in saidpatent, I have discovered that the relation between the length anddiameter of these inverted mantles having carriers adapted to make atight joint with the burner nozzle is of great importance and has adirect. relation to the efliciency of such mantles.

In the closed-top mantles previously used for high pressure lighting,the proportion of length to width was relatively large; that is, themantle was long in proportion to its diameter. I have discovered that inorder to give proper commercial efficiency.

to inverted closed-top mantles used on city Specification of LettersPatent.

pressures, the lengt li con iderably less in proportion to the diameter.In speaking of this relationship, I am referring to the relation ofthese dimensions after shaping and hardening in place on the burner; andI am also referring to the dimensions of the illuminated portion of themantle below the carrier or the ring. In high pressure systems,relatively long closed-top mantles were used because it was foundpracticable to brightly incandesce the whole mantle surface. This is notthe case when such long mantles are used for ordinary city pressures.

I have discovered that the reasons for these facts are as follows: Thegas burned in such inverted closed-top mantles receives part of the airnecessary for combustion through the air inlets to the Bunsen tube ormixing chamber; this is termed the primary air. In addition to this, theburning mixture also obtains a supply of secondary air around andexterior to the mantle to complete or support the combustion. However,the supply of secondary air is more or less contaminated by the risingproducts of. combustion. This stream of products spreadsout as it risesand makes it increasingly difficult for the flame at the intermediateand upper portions of the mantle to obtain an adequate supply of oxygenat or near the mantle surface. The more contaminated with products thespace around the mantle becomes, the farther away from the mantlesurface the flame has to travel before obtaining an adequate supply ofsecondary air. Also the farther the flame travels away from the mantlesurface, the less bright is the illumination of this surface.

In highjpressure systems, the high velocity of the gas issuing from thegas jet results in the entrainment of a relatively large proportion ofprimary air, thus reducing the proportion of secondary airrequiredtocomplete the combustion at the mantle surface. Being thus moreindependent of the supply of secondary air, it has been customary to uselong narrow shapes for such closed-top mantles on high pressure systems.In this way a greater lighting surface and a higher high efiiciency. Therising stream of products was not enough of a factor to cause anynoticeable loss of illumination of the upper part of the mantle.

If it were attempted to use closed-top mantles of such long shape forlow pressure lighting, it would be found that the illumination would beunsatisfactory, this being especially noticeable on the intermediate andupper portions of the mantle. In this case the proportion of primary airentrained by the gas issuing from the jet is much lower in comparisonbecause of the well known fact that in any injector, the proportion offluid entrained by the injector increases as the velocity of the jetincreases. Therefore a larger proportion of secondary air is needed andit is correspondingly important to deliver this secondary air to themantle surface in an uncontaminated condition. It is impossible howeverto accomplish this in a mantle of the usual long shape. Therefore, inthe use of inverted limp or rag mantles with closed-top on citypressures, I have found that it is necessary to limit the length of themantle in proportion to its diameter to much less than that used on limpmantles for high pressure systems in order to give the properillumination to the upper portion of the mantle. By thus limiting thelength, while the primary air is proportionately less, the rising streamof products will be smaller in volume and will be closer to the upperportion of the mantle than they were in longer mantles, and hence theupper portions will be properly illuminated.

By long experimenting, I have found that the proportion of length todiameter in closed-top limp or rag mantles for city pressures must beless than 2, and is preferably 1.6. I also prefer to use the diameterset forth in my Patent No. 1,133,47 0; namely, a mantle less than aninch in diameter when shaped and hardened; and therefore a mantle whenshaped and hardened in place is not over 2 inches in length for a 1 inchdiameter. In actual practice, I find the highest efiiciency is givenwhen the diameter of the shaped and hardened mantle is about 3 inch witha length of about g, inch. I have also found that with this proportionof length, the limp mantle will shape better under burning conditionsand thus give better illuminating power.

I have further discovered, that in these closed-top limp mantles forcity pressure, the weight of mantle material per square inch is animportant factor in giving high efficiency to these limp or rag mantlesfor city pressures.

Closed-top limp mantles heretofore used on high pressures have beenrelatively heavy, weighing about .070 grams per square inch. It waspossible to illuminate such mantles successfully on account of the highflame temperature obtained with the high pressure gas. I have found,however, that such heavy limp closed-top mantles cannot be usedpracticably with city pressures, as the incandescence would not becommercially satisfactory.

In a long series of experiments, Ihave found that the greatestilluminating power for such mantles is obtained with a weight of about.040 to .045 grams per square inch, and that the weight should be lessthan .055 grams per square inch. In speaking of the weight per squareinch, I refer throughout to the weight of the illuminated portion of theshaped and hardened mantle.

In the drawings, Fig. 1 shows a limp mantle constructed in accordancewith my invention and having a screw-carrier ring 3 adapted to screw ona burner nozzle 4 witha tight closure. In Fig. 2, I show the mantle 2after shaping and hardening in place.

The advantages of my invention will be apparent to those skilled in theart, since the lighting power and efliciency of closed-top inverted limpmantles for city pressures are greatly increased.

Variations may be made in the material used for the mantle, theparticular type of the carrier or ring used for making a tight closurewith the burner nozzle, etc., without departing from my invention.

I claim:

1. As a new article of manufacture, a limp inverted mantle having acarrier adapted for close connection with a burner using ordinary gaspressures, said mantle being of a size to shrink to less than 1 inchdiameter when shaped in place, and having, such a proportion of lengthto diameter that when shaped the proportion will be not over 2;substantially as described.

2. As a new article of manufacture, a limp inverted mantle having itsopen end portion adapted to be tightly secured to a reduced burner tipusing ordinary city gas pressures said mantle having its surfacearealess than five times its volume when shaped, and having a proportion oflength. to diameter such thatwhen shaped this proportionwill not be over2; substantially as described.

3. As a new article ofmanufacture, a limp inverted mantle secured to acarrier adapted for connection to a burner nozzle using ordinary gaspressures, said mantle being of a size to shrink to at least one inchdiameter when shaped in place, the proportion of the length of themantle to its diameter being such that when shaped this proportionwillnot be over 2, and the weight of the mantle per square inch of area whenshaped being not over .055 grams; substantially as de scribed.

4. As a new article of manufacture, a limp inverted mantle adaptedto betightly secured to a reduced burner tip using ordinary city gaspressures, mantlehaving its surface area less than five times its volumewhen shaped, and the Weight of the shaped mantle being not over .055grams per square inch; substantially as described.

5. As a new article of manufacture, a limp inverted mantle having acarrier adapted to make a close connection With a burner nozzle usingordinary gas pressures said mantle being of a size to shrink to at leastone 10 inch diameter When shaped in place and bemy hand.

SVERRE GULBRANDSEN. Witnesses:

Jos. T. CURRAN, J. H. JOHNSON.

Copies of this patent may be obtained for five cents each, by addressingthe "Commissioner of Patents, Washington, D. G.

